The Terrifying Reality Of Reaching The Edge Of The Universe（原声文稿）

You strap into the seat, look out the window at the launch pad, and make a decision that every reasonable person on earth would advise against.

You are going to fly in a straight line until you hit the edge of the universe. The engines ignite.

The whole ship shakes like a washing machine full of bricks.

Your body is pressed into the seat so hard that lifting your arm feels like a part -time job.

Eight and a half minutes later, the shaking stops, and you are floating. You are in orbit. This feels like progress. It is not.

You have traveled about 400 kilometers.

The universe has not noticed. A few days later, the moon slides past your window, gray and silent.

A few months after that, Mars.

Then the long, boring dark between the planets.

The sun shrinks with every passing week until it stops looking like a sun and starts looking like a very bright star. And here is your first problem.

The fastest object humans have ever sent out of the solar system, Voyager 1, took about 35 years just to reach interstellar space.

At that speed, the nearest star would take you more than 70 ,000 years. You pack snacks for a much shorter trip.

So you do what every science fiction writer does when the numbers get rude. You switch on an engine that does not exist yet.

A magical drive that never runs out of fuel and pushes you forward at a steady 1G.

That means the ship accelerates at exactly the rate that would make you fall on Earth. with. Your feet settle onto the floor.

You can walk around, you can make coffee. Gravity is back, and it is now powered by pure optimism.

One G does not sound fast, but it never stops.

Every second, you go a little faster than the second before.

After a few weeks, you are crossing the old orbit of Pluto in the time it takes to finish a podcast.

After about a year, you are travelling close to the speed of light.

This is where the universe starts behaving strangely.

You look out the front window and something is wrong with the stars.

They are crowding together ahead of you, bunching toward the center of your view like they are all trying to get into the same lift. They are also changing color.

The ones in front glow bluer, the ones behind you stretch toward red, thin out, and fade. Nothing is wrong with the stars.

This is what the sky looks like when you are moving that fast. Your own speed is bending the light you see. The second strange thing is quieter and much worse.

You check your clock. It says you have been gone for a few years. Then you check the message feed from Earth.

The messages are arriving slower and slower, and the dates on them are wrong. Not slightly wrong.

Decades are passing back home while your coffee is still warm. That is time dilation.

The faster you go, the slower your clock ticks, compared to everyone you left behind. From your seat, the trip feels short. From Earth, you are disappearing into the future. Your family is getting older in every message. Then the messages are from your family's children.

Then from people you have never met, who seem politely confused about why you are still out there. And then there is the dust.

Space between the stars is not perfectly empty.

There is roughly one atom of hydrogen floating around in every sugar cube size chunk of it. At walking speed, that is nothing.

At nearly the speed of light, every one of those atoms slams into the front of your ship like a tiny particle beam.

Together, they become a constant storm of radiation pouring into the nose of the ship.

A single grain of dust, smaller than a speck of flour, would hit you with the energy of a bomb.

So your ship needs a thick shield on the front, and you need to stay behind it.

The fastest ship in history is now also a ship where you are not allowed to sit near the window. Still, the shield holds.

And when you finally look back, you see something no human has ever seen with their own eyes. The Milky Way.

Not as a pale stripe across the night sky, sky, but the whole thing. A huge glowing spiral.

Hundreds of billions of stars. Hanging behind you in the black.

Somewhere in one of those arms is a small yellow star you used to call the sun. You cannot find it. Nobody could. You have left the galaxy.

What is out here is the emptiest place you have ever been. Between galaxies there are no stars nearby at all.

The darkness is so complete that the faint smudges of other galaxies are the only lights in the sky.

The temperature outside the hull is a few degrees above absolute zero.

The last of the warmth of the universe is a faint glow left over from the beginning of time.

Ahead of you, one smudge grows larger, Andromeda, our closest big neighbor galaxy, about two and a half million light years away.

Light itself needs two and a half million years to make this trip.

For you, thanks to time dilation, the ride takes only a couple of decades on your clock.

You fly past Andromeda's spiral arms with one hand on the controls, and the other holding a coffee that has gone cold for the four thousandth time.

Back on Earth, two and a half million years have passed. Every language you know is gone.

Every country you know is gone. Humans may be gone.

You will never know, because the message feed has been silent for a very long time.

You are now the most distant human who has ever existed, and you have barely started.

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past more galaxies, past whole clusters of galaxies, hundreds and thousands of them packed together like glowing swarms, past long threads of galaxies stretching across space like the strands of a gigantic web with enormous empty voids in between, and slowly you start to notice the thing that will ruin your entire mission.

The galaxies ahead of you are moving away. Not because of anything you did.

Every distant galaxy is drifting away from every other distant galaxy, and the farther away a galaxy is, the faster it seems to retreat. The universe is expanding.

Space itself is stretching between everything, like dough rising in an oven with raisins pulling apart. At first, this is a minor annoyance.

Your destination keeps getting a little farther away while you travel toward it. Fine. You are fast. But here is the part almost nobody expects.

The expansion is not slowing down, it is speeding up.

Something in the universe, which scientists call dark energy, is pushing space apart faster and faster.

Galaxies that are far enough away are now being carried away from you faster than light could ever travel toward them.

That is not a typo, nothing can move through space faster than light.

But space itself can stretch faster than that.

You are not racing the galaxies, you are racing the floor they are standing on. one. So you push harder, 1g forever.

You are traveling ridiculously close to the speed of light, and it does not matter. There is a limit.

Right now, everything more than roughly 16 billion light years away is permanently out of reach, not just for you, for everyone, for light itself.

A beam of light leaving Earth today will never arrive there.

No matter how long you fly, no matter how much fuel your imaginary engine burns, you will never cross that line. line.

Scientists call it the cosmic event horizon. You can call it the moment your plan officially became a hobby.

And now the really strange part.

Looking back from Earth, astronomers can see things much farther away than that.

The observable universe stretches about 46 billion light years in every direction.

Light that left those places long ago has already reached us. You can see things you can never touch.

You can look at galaxies, map them, them, give them names, and still never ever arrive. So what about the edge? The actual edge? The wall? The place where the universe stops?

Here is the answer you were not hoping for. As far as anyone can tell, there is no edge.

The farthest thing you can see from Earth is a faint glow called the cosmic microwave background.

It looks like a wall at the end of everything, but it is not a wall in space. It is a wall in time.

It is the oldest light there is, released when the whole universe was hot and glowing, roughly 380 ,000 years after it began.

You are not looking at the end of the universe, you are looking at its baby photo.

And the observable universe is not a room with walls. It is a bubble centered on whoever is doing the observing.

On Earth, the bubble is centered on Earth.

On your ship, it is centered on you. Every time you move, the bubble moves with you. you.

You fly toward the edge and the edge comes with you, like the horizon on a road trip. You can chase it for billions of years and never get closer.

So you slow down, look around, and here is what you find. Galaxies. In every direction.

The same kinds of spirals and blobs you left behind spread out more or less evenly across the dark.

No sign that says end. No glowing boundary, no cliff.

The universe out here looks almost exactly like the universe back home.

As far as anyone knows, it either goes on forever, or it curves back on itself in a way that has no edge at all, like the surface of a ball where you can walk forever without falling off.

You have traveled farther than any human could imagine, to discover that you are standing in the middle again. Then you think about home. From your clock, a human lifetime might have passed.

From the universe's point of view, billions of years are gone.

The sun was always going to swell into a red giant someday, a few billion years from when you left. It probably already has.

Earth is either scorched, swallowed, or something completely different from the world you knew.

And even if you wanted to tell someone where you are, you cannot.

You are now far enough away that any signal you send home will be carried off by the expansion of space before it ever gets there.

Your message would chase the Milky Way forever and never catch up. You are not lost.

You know exactly where you are. It is just that nobody else will ever be able to know.

So this is what actually happens if you try to reach the edge of the universe. You leave your planet, your star, and your galaxy.

You watch the stars bend in front of you and your family age and fast forward.

You fly through a radiation storm, cross the emptiest places that exist, and outlive every civilization you ever heard of.

And at the end of it all, the universe hands you a very polite answer. There is no edge to reach.

There is only more universe, a horizon that moves every time you do, and a cold cup of coffee that has now technically been cold for billions of years.

Somewhere out there you are still flying, and somehow you are still in the middle.